It is common in the automotive industry to fabricate automotive vehicle bodies through the attachment of a plurality of metal or plastic body panels to a metallic sub-frame. The sub-frame cooperates with the outwardly facing body panels, to support and reinforce the body panels and carry the loads required in normal vehicle applications.
Recent practice in the automotive industry is utilization of plastic fabricated parts for some or all of the external body panels. The fastening of plastic outer body panels to a metallic inner structural sub-frame presents certain unique problems not previously dealt with in the automotive industry.
For example, conventional fastening techniques often distort the body panel near the point of attachment. In addition, common fastening techniques often include time consuming and sometimes difficult spatial adjustment of body panels in relation to each other. Specifically, the spatial relationship between adjacent body panels must be adjusted until the respective edges of the adjacent body panels are even or flush with each other. This affords aerodynamic advantages which are directly related to energy consumption of the vehicle and also adds particular aesthetic value to the overall appearance of the vehicle.
In addition to the assembly process, the spatial relationship of adjacent body panels is important when a vehicle body panel is damaged and must be repaired. Often these damaged body panels are removed and repaired or replaced with a new body panel. At this point, it is again necessary to spatially relate adjacent body panels to achieve maximum flushness between the outer respective edges of the adjacent panels.
One solution employed to overcome the above problems is disclosed in U.S. Pat. No. 4,868,968 to Dixon et al., also assigned to the assignee of the present invention. Dixon et al. discloses an assembly system in which a flanged cup is inserted into a hole in a metal sub-frame and a heat curing thixotropic plastic/adhesive is applied into the recess of the cup.
A heated fixture is next brought into contact with the plastic/adhesive to mold the adhesive to a predetermined height above the metallic sub-frame. The heated fixture simultaneously cures the plastic/adhesive and forms a fastener receiving aperture extending from its outer face into the cup area. Thus, in this system an intermediate plastic structure for positioning the plastic outer body panel with respect to the metal sub-frame is manufactured on the panel assembly line with the spatial relationship, i.e. the height of the intermediate plastic structure being set by the fixture, and not by a pre-positioning of the actual body panel itself.